A caustic element emitted from an air conditioning unit in the American sector of the International Space Station has forced all of the astronauts to take refuge in the Russian section, Russia’s space agency Roscosmos said Wednesday.

“At 11:44 a.m. [08:44 GMT], a caustic element from an air conditioning unit in the American segment of the International Space Station was discharged into the station’s atmosphere. The American segment on the ISS is currently isolated, the crew is safe and located in the Russian segment,” Roscosmos said in a statement.

“The crew’s safety was provided for thanks to the coordinated and quick actions of the cosmonauts and astronauts themselves, as well as operative control groups in Moscow and Houston,” the statement concluded.